Suntan is the code name given to a prototype surveillance
plane developed under tight secrecy in the 1950's.
Developed by Lockheed Martin
, the Suntan, officially designated as CL-400, was designed to replace the U-2
spyplane. It was a huge but very light aircraft which was intended to fly at Mach
2.5, thanks to two Pratt & Whitney
hydrogen burning air-turbo-ramjet
engines. A facility in Florida was built for the sole purpose of testing these engines. Unfortunately they proved to be the cause of Suntan's failure, as project was canceled due to the immense cost of hydrogen
fuel, with only four prototypes made.
After cancellation in 1958, the project was renamed to "Gusto" and moved to the CIA. In September 1959, Lockheed was again given the chance to build it. The project was renamed "Oxcart" (these folk and their kooky codenames) and the Suntan information and specs were incorporated into a design that would eventually became the SR-71 Blackbird.
The Suntan was an odd looking bird. Visually, it appears to be a bastard love-child between an X-15 and SR-71. The two massive air-turbo-ramjet engines were located on the ends of the wings, tossing in a bit of Northrop F-89 Scorpion to the mix, as the engines look like the Scorpion's weapon pods.
It is rumored among conspiracy theorists that the information gained during the development of the Suntan—mainly the engines—has been incorporated into the Aurora.
Nothing was heard about the Suntan for over 20 years.